'Supernatural' season 12 episode 16 spoilers: Dean joins the British Men of Letters; Mary Winchester staying for good?

Dean (Jensen Ackles) finally gave in to working with the British Men of Letters. Meanwhile, Mary Winchester (Samantha Smith) appears to be staying for the long haul.

Previously on "Supernatural" season 12, Dean finally agreed to work with the British Men of Letters after Sam (Jared Padalecki) confessed that their previous assignments came from them. But Dean might not be willing to forgive Mary just yet.

According to an interview with TVLine, Smith, who portrays Mary, shared that Dean is very stubborn when it comes to the British Men of Letters.

"Dean is much more black-and-white. She's going to have to earn his faith. He loves her, but I don't think he understands her yet," shared Smith.

But Mary won't give in to Dean's stubbornness just yet. "Mary is willing to jeopardize all of that to do what she thinks is right, ultimately, for the good of her children, even if it makes them not like her," Smith added.

Mary will have a lot of time to prove her point, as Smith also shared that, as far as she knows, her character is staying for the long haul in season 12.

However, on the next episode of "Supernatural" season 12 titled, "Ladies Drink Free," Dean and Sam will be working with Mick (Adam Fergus) from the British Men of Letters on a case involving werewolves.

"The three men run into Claire Novak (Kathryn Love Newton), also working the hunt. However, the reunion is short lived after Claire is bitten and the brothers race to find a way to help her before she turns," the episode listing on The Futon Critic reads.

As seen from the episode promo, Claire tells Sam and Dean that Mick isn't really much help to them, indicating that not all the British Men of Letters are highly skilled in fighting demons and supernatural beings.

"Supernatural" season 12 airs every Thursday night at 8 p.m. EDT on The CW.